Appetizers and Lessons for Mathematics and Reason 
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||Définition d'une variable || Algèbre || Arithmetique || Logique ||La raison basée sur les règles et modelés||

Online Volumes (Book Orders)
1,  Elements of Reason.
1A. Pattern Based Reason 
1B. Math Curriculum Notes
2. Three Skills for Algebra
   Three Skills for Algebra
3. Why Slopes & More Math
 Avid Readers: Try Pattern Based Reason 
chaps  1 to  17  in  Three Skills for Algebra.
More Site Areas 
1. Solving Linear Equations  
2. Fractions Ratios Rates Proportions, Units
3. Euclidean Geometry
4. Analytic Geometry/Functions 
5. Number Theory
6. Calculus Introduction
7. Complex Numbers 
8. Quebec Maths Education  
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9. Secondary IV(?) maths
10. Real  Analysis 
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12. Electric Circuits Etc  
13. Algebra, Odds & Ends, Etc
14  LAMP - Course re Design Plans
15. Math Education Essays
Teacher-Tutor Info & How-TOs
1. Arithmetic Reference
2. Algebra Starters 
3. More Algebra 
4. Geometry Starters
5. More Geometry
6. Calculus Modifiers 
7. Multiple Logics in Maths
8. Math Ed. Issues


YOU are better than YOU think. Show yourself  how:  

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Read  logic chapters 1 to 5  in online volume Three Skills for Algebra  for greater skills & confidence in  work 
and study

Learn to read notes and textbooks like a lawyer, so that no nuance, no subtlety and no clause escapes your attention.

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 Logic chapters 1 to 5  re- appear not in sequence, as is or longer,  in  Volume 1A,  Pattern Based Reason, Bon Appetite.

Logic Mastery
 Amazing, Amusing, Amorous,  Delicious, Delightful, Edifying, Strengthening Elixir. 
It eases work & learning difficulties Makes the hard easier. Opens eyes. Leads to greater precision.
in reading and
writing

Logic mastery makes the hard, easier. Logic mastery  leads to better, stronger and richer comprehension.  Logic mastery  improves reading and writing.  Logic mastery ease learning difficulties.  Logic mastery gives a headstart.  In sum, logic mastery  will develops critical thinking, improve reading and writing, and give a firmer base for work and studies at many levels. Good luck.


After logic  (a) continue reading Three Skills for Algebra, chapters 8 to 14  and do so alongside site area on solving liinear Equations ; or (b) see this calculus starter lesson and Volume 3, Why Slopes  & More Math, chapters 2 to 6;

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Caution: Site advice is approximately correct, for some circumstances, not all. That leaves room for thought

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What may be learnt and when depends on how skills and concepts are developed. Making the hard easier and clearer will allow earlier & richer development of skills and concepts.


 

Addition Preliminaries

Physical Interpretation 


Addition Via Counting

To illustrate this, take for instance two bags of marbles. Say one bag has 13 marbles and another 15. Ask your child to put the two bags together, and count how many there are. Now take two bags, one with 13 buttons and another with 15 buttons. Ask your child again to count how many there are. This shows the total number of objects does not depend on their type or kind. Redo this addition experience with varying numbers.

Addition via Counting may lead to the additon table

    + 1 2 3 4 5 6 7 8 9
    1 2 3 4 5 6 7 8 9 10
    2 3 4 5 6 7 8 9 10 11
    3 4 5 6 7 8 9 10 11 12
    4 5 6 7 8 9 10 11 12 13
    5 6 7 8 9 10 11 12 13 14
    6 7 8 9 10 11 12 13 14 15
    7 8 9 10 11 12 13 14 15 16
    8 9 10 11 12 13 14 15 16 17
    9 10 11 12 13 14 15 16 17 18

    If you do or review it with a student, observe how adding n+1 to number is one more than adding n to the number. That provides a mechanism for filling in the table by rows (horizontally from right to left) and by columns (vertically from top to bottom).

Students should know the sums of all pairs of digits from 1 to 9, as well as how to add 0 and 10 to a single digit number. Filling in the addition table is a good exercise.

Addition with Decimals - How to Justify

Besides column methods for addition shown below, there are column methods for subtraction, multiplication and even long division. All methods, some more directly than others, take advantage of decimal place value. 

Single to Triple Digit Examples - with carries

Provide the following experiences (and similar ones).

  • By counting 3 ones added to 4 ones is 7 ones. On paper this can be written in the shorthand form

                    3
                  + 4
                ----------
                    7
                ----------
        
  • By counting 8 ones added to 7 ones yields 15 ones. On paper this can be written in the shorthand form

                    8
                  + 7
                ----------
                   15
                ----------
    
  • By counting, 12 ones added to 25 ones is 37 ones or three tens and 7 ones. On paper this can be written in the shorthand form

   12         (read backwards: 2 ones plus 1 ten )
 + 25         (read backwards: 5 ones plus 2 tens)
 ------     added together gives
   37                           7 ones plus 3 tens
 ------

                    
  • (Carrying Illustrated). Now lets try 144 plus 85 without counting. On paper this can be written in shorthand form and longhand form as follows.

 244      ( 4 ones plus 4 tens plus 2 hundreds )
  85      ( 5 ones plus 8 tens)
 -----     added together gives
           9 ones plus 12 tens plus 2 hundreds
 -----

                     

But the 12 tens is the same as 2 tens plus 1 hundred. Thus replacement suggests the result

 

                ____________________________________\_
                                                    / 

                                                          

  244          (read  2 ones plus 4 tens plus 2 hundreds ) |
   85          (read  5 ones plus 8 tens)                  |
----------     added together gives                        |
  329           9 ones plus 12 tens plus 3   hundred       |
---------    or 9 ones plus  2 tens plus 2+1 hundreds      |
  1          or 9 ones plus  2 tens plus 3   hundreds     \|/


               /____________________________________________
               \  

shorthand   +      Longhand Representations, respectively, 
                of the addition

                  

The one in the last row denotes a carry. The on the left and the words on the right represent the same number. Here the shorthand expressions requires less work to write, but its justification requires a knowledge of the longhand form. In the following examples, we write the shorthand form, then do the calculation with the help of the longhand representation and lastly return to the shorthand form. With practice, the long representation and explanation of the shorthand will be understood, and it need not be written down. The calculation is then done and represented via its shorthand representation.

Examples: 

Addition without Conversions (Carries)

Steps

  1. add units
  2. add tens
  3. add hundreds

Conclusion: 243 + 452 = 695.

Addition with Conversions (Carries)

Steps

  1. Add units: 9 and 6 give 15 = 5 + 10 or a 5 in the unit column with one ten to carry over into the ten's column.
  2. Add  tens: 5 + 2 + the 1 from the carry give 8.
  3. Add hundreds: 4 + 8 hundreds give 10 + 2 hundreds or 2 in the hundred column with a one thousand to carry over to into the thousands column.
  4. Add thousands. the carry of 1 + 2 + 4 = 7. Done
  5. Conclusion: 2459 + 4826 = 7285.

 

 

 


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Number Theory

Start of Number Theory

Origins of Counting or Tallying
Adding Wholes
Multipling Wholes
Distributive Law  Preamble
Distributive Law for Wholes
Consequences
More Consequences
What is a Fraction
Compound Fractions

Number Theory
Continued


Decimal Place Value
Place Value Reinforcement
Comparison Method
Addition Method
Subtraction Methods
Multiplication Methods
Division Methods
Remainder Arithmetic I
Primes & Composites
Primes Factorization Theorem
Primes & Composites
Prime Factorization Aids
Prime Factorization Examples
Counting  Whole No.  Factors
Arithmetic Videos
Square Roots  & Primes
Long Division Continued
Fractions & Decimals
Fractions as Decimals
1 = 0.999 Recurring
Infinite Decimals Expansion Arithmetic
Ratio of Simple Fractions
Ratio of Decimal Fractions
Unsigned Reals Numbers
Signed Coordinates
Plane Vectors
Horizontal Vectors
Adding Vector Multiplies
Adding Signed Numbers
Multiplying Signed Numbers
Distributive Law for Reals
Real Numbers Axioms
Remainder Arithmetic II

Related Site Pages:


For online automated help in senior high school maths & calculus, visit  quickmath.com  For Automatic Calculus and Algebra Help with derivatives, integrals, graphs, linear equations, matrix algebra, visit calc101.com  With  overlap, each site quickmath & calc101offers a different range of services, some free, some not, all based on webmathematica. Good luck

Food for thought: Try the Twiddla Whiteboard. In principle, it  allows to people to draw and chat together online on a copy of this webpage or a clean sheet. The chat may be via text or audio.  Visit www.twiddla.com to set up whiteboards to work with the webpage of your choice..

 


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a 1983 McGill. Ph. D. in mathematics
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